Add nim product

codes/Misc/NimProd.cpp

@@ -0,0 +1,20 @@
+#define rep(i, r) for (int i = 0; i < r; i++)
+struct NimProd {
+  llu bit_prod[64][64]{}, prod[8][8][256][256]{};
+  NimProd() {
+    rep(i, 64) rep(j, 64) if (i & j) {
+      int a = lowbit(i & j);
+      bit_prod[i][j] = bit_prod[i ^ a][j] ^
+        bit_prod[(i ^ a) | (a-1)][(j ^ a) | (i & (a-1))];
+    } else bit_prod[i][j] = 1ULL << (i | j);
+    rep(e, 8) rep(f, 8) rep(x, 256) rep(y, 256)
+      rep(i, 8) if (x >> i & 1) rep(j, 8) if (y >> j & 1)
+        prod[e][f][x][y] ^= bit_prod[e * 8 + i][f * 8 + j];
+  }
+  llu operator()(llu a, llu b) const {
+    llu res = 0;
+    rep(e, 8) rep(f, 8)
+      res ^= prod[e][f][a >> (e * 8) & 255][b >> (f * 8) & 255];
+    return res;
+  }
+};

pdf/content.yaml

@@ -424,3 +424,6 @@
     - name: Montgomery
       path: Montgomery.cpp
       verified: 012165f
+    - name: Nim Product
+      path: NimProd.cpp
+      verified: